Sedimentary evolution and effects of structural controls on the development of the Zambezi mixed turbidite-contourite system (Mozambique channel, southwest Indian Ocean) since the Oligocene

Type Article
Date 2022-04
Language English
Author(s) Fierens RuthORCID1, Droz Laurence1, Jouet GwenaelORCID2, Rabineau MarinaORCID1, Raisson F.ORCID3, Babonneau Nathalie4, Robin C.5, Jorry StephanORCID2
Affiliation(s) 1 : CNRS, Université Bretagne Occidentale, Ifremer, Geo-Ocean, UMR6538, IUEM, 29280, Plouzané, France
2 : Ifremer, Université Bretagne Occidentale, CNRS, Geo-Ocean, 29280, Plouzané, France
3 : Clastic Sedimentology Group, TotalEnergies, 64000, Pau, France
4 : Université Bretagne Occidentale, CNRS, Ifremer, Geo-Ocean, UMR6538, IUEM, 29280, Plouzané, France
5 : CNRS, Géosciences Rennes, UMR6118, Université de Rennes, Rennes, 35042, France
Source Marine And Petroleum Geology (0264-8172) (Elsevier BV), 2022-04 , Vol. 138 , P. 105532 (22p.)
DOI 10.1016/j.marpetgeo.2022.105532
WOS© Times Cited 2
Keyword(s) Zambezi turbidite system, Mozambique Channel, Multichannel seismic profiles, Turbidite, Contourite, Tectonic, Late Cenozoic
Abstract

High-resolution multichannel seismic reflection data that spans significant parts of the Mozambique margin offshore the Zambezi River permits the study of the Oligocene to present architectural evolution of the Zambezi turbidite system. In this time frame, five major depositional units are recognized that evidence a widespread spatial and temporal occurrence of both turbiditic and contouritic sedimentation. They indicate that the sedimentary regime within the turbidite system changed from dominantly aggradational during the Oligocene to mainly erosional during Miocene to an interplay of erosional and depositional processes during the Plio-Quaternary. Different episodes of incision, linked with the Serpa Pinto, Angoche and Zambezi valleys, are recognized in the upstream portion of the Zambezi Fan and highlight a westward (anticlockwise) shift of feeding axes. The central portion of the Zambezi Valley was affected by a progressive structural doming during the Miocene. The dominance of long-lasting erosional processes generated by the continuous rise of the seabed led to a deep entrenchment of the Zambezi Valley. This tectonically-controlled over-incision is believed to be the cause of the absence of Miocene levees, and has played an important role in the stabilization of the valley at its current position. Finally, our study revealed a quasi-constant development of contourite accumulations since the Late Miocene that occur most often synchronous with turbiditic sedimentation. The present study offers unique insight into the controls and stages of development of one of the largest turbidite systems in the world and demonstrates especially its susceptibility to structural activity.

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Fierens Ruth, Droz Laurence, Jouet Gwenael, Rabineau Marina, Raisson F., Babonneau Nathalie, Robin C., Jorry Stephan (2022). Sedimentary evolution and effects of structural controls on the development of the Zambezi mixed turbidite-contourite system (Mozambique channel, southwest Indian Ocean) since the Oligocene. Marine And Petroleum Geology, 138, 105532 (22p.). Publisher's official version : https://doi.org/10.1016/j.marpetgeo.2022.105532 , Open Access version : https://archimer.ifremer.fr/doc/00745/85666/